Questions and Answers

Ford F350 Pickup Refueling Problems Q. My son purchased a 1996 Ford F350 Pickup and has been unable to add fuel to the front tank. The fuel will blow back on you. We have removed the fill line, and it is clear and free of obstruction and no kinks. We are not familiar with the vent system but have considered changing what appears to be a plastic vent assembly located on top of the fuel tank. Your assistance would be greatly appreciated. Thank you...

A. If the Evaporative Valve Assembly gets clogged or broken, it would cause the symptoms you described.

PURPOSE:
The fuel vapor valve mounted on the top of the fuel tank is used to control the flow of fuel vapor entering the fuel tank vapor delivery line which sends vapor forward to the fuel vapor canister in normal circumstances.

OPERATION:
If excessive pressure is generated inside the tank, the purge port opens up, allowing fuel vapor to escape to the atmosphere, and stabilizes pressure inside the fuel tank. The fuel vapor valve has a head valve which prevents the fuel tank from overfilling during refueling operation. The fuel vapor valve also has a spring supported float assembly, which prevents liquid fuel from entering the vapor delivery line during severe handling, steep grades or in the event of vehicle rollover.